Heat exchange assembly

ABSTRACT

A roofing panel ( 13 ) incorporating a heat exchange assembly is described, the roofing panel including: an internal fluid passageway ( 51 ) formed between a pair of spaced substantially parallel internal sheets ( 16, 17 ) for the passage therethrough of a fluid; respective external passageways ( 52, 53 ) formed between each internal sheet and a respective external sheet ( 21, 20 ) spaced from and substantially parallel to a respective internal sheet, and spacing ribs ( 18, 22, 24 ) between the sheets and forming with the sheets a plurality of fluid conduits ( 19 ) within the fluid passageway and a plurality of external conduits ( 23, 25 ) within the external passageways; wherein the panel is sealed at the sides thereof by the spacing ribs and is open at the ends thereof to provide access to the conduits which extend from one end of the panel to the other end thereof.

TECHNICAL FIELD

This invention relates to a heat exchange assembly and to a method ofheat exchange.

The invention has particular but not exclusive application to heatexchangers for use in a roof and to solar heat exchangers, although theinvention may be utilised in other than roofing systems and in otherthan solar powered systems.

BACKGROUND OF INVENTION

Heat exchange assemblies are known in which a roofing panel is comprisedof a pair of spaced apart polycarbonate sheets and in which water isheated as it flows between the sheets. International patent applicationPCT/NO95/00127 in the name of Rekstad illustrates such a system.

SUMMARY OF INVENTION

The present invention aims to provide an alternative to known heatexchange assemblies, known methods of heat exchange and known roofingpanels incorporating a heat exchange assembly.

This invention in one aspect resides broadly in a heat exchange assemblyincluding:—

an internal passageway formed between a pair of spaced substantiallyparallel internal sheets, and

respective external passageways formed between each said internal sheetand a respective external sheet spaced from and substantially parallelto a respective internal sheet;

said pair of internal sheets at the ends of said internal passagewayextending beyond said external sheets at the ends of said externalpassageways thereby facilitating fusion welding to said internal sheetsat the ends of said internal passageway.

Although the invention is described with reference to the preferredembodiments as having one internal fluid passageway formed between apair of spaced substantially parallel internal sheets, it is to beunderstood that there may be a plurality of internal passageways formedbetween respective pairs of spaced substantially parallel internalsheets. Thus the heat exchange assembly may include more than foursheets.

The sheets can be separated by any suitable spacing means such as postsor the like. However it is preferred that the heat exchange assemblyincludes:—

spacing ribs between said sheets and forming with said sheets aplurality of fluid conduits within said internal passageway and aplurality of external conduits within said external passageways.

Preferably the heat exchange assembly includes:—

fluid inlet means at one end of said internal passageway or saidexternal passageways for the inflow of fluid in the heat exchangeassembly, and

fluid outlet means at the other end of said internal passageway or saidexternal passageways for the outflow of fluid from the heat exchangeassembly.

The external passageways can contain another liquid however it ispreferred that the heat exchange assembly includes:—

gas inlet means at one end of the other of said internal passageway orsaid external passageways for the inflow of gas to the heat exchangeassembly, and

gas outlet means at the other end of the other of said internalpassageway or said external passageways for the outflow of gas from theheat exchange assembly;

whereby said internal passageway or said external passageways is/areadapted to receive or contain a gas for effecting heat exchange with afluid in the other of said internal passageway or said externalpassageways.

The gas can be air whereby the external passageways comprise an opensystem. Alternatively in a closed system the gas can be an inert gas.

The heat exchange assembly can be of any suitable shape andconfiguration consistent with the above. However it is preferred thatthe heat exchange assembly constitutes a panel sealed at the sidesthereof by said spacing ribs and open at the ends thereof to provideaccess to said conduits which extend from one end of the panel to theother end thereof.

Preferably the panel is suitable for use as roofing.

Accordingly in another aspect this invention resides broadly in aroofing panel incorporating a heat exchange assembly, said roofing panelincluding:—

an internal fluid passageway formed between a pair of spacedsubstantially parallel internal sheets for the passage therethrough of afluid;

respective external passageways formed between each said internal sheetand a respective external sheet spaced from and substantially parallelto a respective internal sheet, and

spacing ribs between said sheets and forming with said sheets aplurality of fluid conduits within said fluid passageway and a pluralityof external conduits within said external passageways;

said pair of internal sheets at the ends of said internal passagewayextending beyond said external sheets at the ends of said externalpassageways thereby facilitating fusion welding to said internal sheetsat the ends of said internal passageway, said panel being sealed at thesides thereof by said spacing ribs and being open at the ends thereof toprovide access to said conduits which extend from one end of the panelto the other end thereof.

Fluid and or gas supplies may be connected directly to the respectiveconduits at the ends of the panel. However it is preferred that the heatexchange assembly includes an inlet manifold and an outlet manifold atrespective ends of the panel.

Preferably the inlet manifold and the outlet manifold include the fluidinlet means and the fluid outlet means respectively. The inlet manifoldand the outlet manifold also preferably include the gas inlet means andthe gas outlet means respectively.

The heat exchange assembly may also include pressure relief means forrelieving the pressure in the fluid passageway generated by heatingfluid therein. In a preferred embodiment the relief means is a riserpositioned in the fluid inlet and/or fluid outlet means.

In another aspect this invention resides broadly in a heat exchangeassembly including:—

an internal passageway formed between a pair of spaced substantiallyparallel internal sheets, and

respective external passageways formed between each said internal sheetand a respective external sheet spaced from and substantially parallelto a respective internal sheet;

fluid inlet means at one end of said internal passageway or saidexternal passageways for the inflow of fluid in the heat exchangeassembly;

fluid outlet means at the other end of said internal passageway or saidexternal passageways for the outflow of fluid from the heat exchangeassembly;

gas inlet means at one end of the other of said internal passageway orsaid external passageways for the inflow of gas to the heat exchangeassembly, and

gas outlet means at the other end of the other of said internalpassageway or said external passageways for the outflow of gas from theheat exchange assembly;

whereby said internal passageway or said external passageways is/areadapted to receive or contain a gas for effecting heat exchange with afluid in the other of said internal passageway or said externalpassageways.

In another aspect this invention resides broadly in a manifold forconnection to a panel as defined above, the manifold including:—

fluid communication means for the inflow or outflow of fluid to or fromthe fluid conduits, and

gas communication means for the inflow or outflow of gas to or from theexternal conduits.

The manifold can be connected to the panel in a number of ways. It couldfor example be a split tube adapted to be retained on ends of the panelby the resilience of the split tube. Alternatively the manifold can beultrasonically welded to the panel. In a preferred embodiment themanifold includes receiving means for receiving the internal sheets andthe external sheets whereby the fluid communication means and the gascommunication means are sealingly connected to the fluid passageway andthe external passageways respectively.

It is preferred that the manifold is an extrusion and the fluidcommunication means and the gas communication means are channels in theextrusion.

In a further aspect this invention resides broadly in a heat exchangepanel including:—

an internal fluid passageway formed between a pair of spacedsubstantially parallel internal sheets for the passage therethrough of afluid;

respective external passageways formed between each the internal sheetand a respective external sheet spaced from and substantially parallelto a respective internal sheet, spacing ribs between the sheets andforming with the sheets a plurality of fluid conduits within the fluidpassageway and a plurality of external conduits within the externalpassageways, and

manifold means including fluid communication means for the inflow oroutflow of fluid to or from the fluid conduits, and gas communicationmeans for the inflow or outflow of gas to or from the external conduits;

wherein the panel is sealed at the sides thereof by the spacing ribs andis open at the ends thereof to provide access to the conduits whichextend from one end of the panel to the other end thereof.

DESCRIPTION OF DRAWINGS

In order that this invention may be more easily understood and put intopractical effect, reference will now be made to the accompanyingdrawings which illustrate a preferred embodiment of the invention,wherein:—

FIG. 1 is a schematic illustration of the heat exchanger of the presentinvention in use;

FIG. 2 is a schematic illustration showing roofing panels in accordancewith the present invention positioned on a roof;

FIG. 3 is a generalised perspective view of a heat exchanger panel inaccordance with the present invention;

FIG. 4 is a detailed partial perspective view of a the heat exchangerpanel of FIG. 3;

FIG. 5 is a sectional elevation along lines AA in FIG. 2 illustratingthe interconnection of adjoining heat exchanger panels along their sidesand their fixing to the roofing frame;

FIG. 6 is a perspective view of the lateral connector illustrated inFIG. 5;

FIG. 7 is a sectional elevation illustrating in detail theinterconnection of adjoining heat exchanger panels along their sides;

FIG. 8 is a sectional elevation illustrating a manifold for the supplyof fluid and gas to the heat exchange panel connected to a panel, and

FIG. 9 illustrates a riser for relieving the pressure in the fluidpassageway.

DESCRIPTION OF PREFERRED EMBODIMENT OF INVENTION

As can be seen in FIG. 1, water is pumped from a water storage tank 11by pump 12 to a heat exchanger 13 positioned on the roof of house 14.The heated water is then utilised by systems 15 and returned to tank 11.It is to be understood that this diagrammatic illustration is merelyrepresentative. The heat exchanger need not be located on a roof and canbe positioned for solar operation at an appropriate angle of inclinationon the ground or on a free standing support frame. Neither as will beobvious from a full reading of the specification, need the operativeenergy source be solar. Neither are the uses to which the heat exchangercan be put be limited to a house, and these uses can be varied.

Typical uses include underfloor or in-slab heating, greenhouse heating,swimming pool heating and hot water systems. However it is to beunderstood that the heat exchanger of the present invention is notlimited to heating and can be used in cooling systems. However forillustrative purposes the following description will relate to a heatexchanger included in a panel suitable for roofing a house.

As can be seen in FIG. 2, a plurality of roofing panels 13 arepositioned side by side to constitute the roof on that side of the roofof dwelling 14 receiving most direct sunlight. The panels are preferablythe standard width between roof trusses ie 900 mm and of variablelength. The panels can also be made to a standard length, ie 12 mm, andcan be cut to size to suit individual roofing requirements.

As is seen generally in FIG. 3, panel 13 has open ends 54 and 55providing communication with a central passageway 51 sandwiched betweenexternal passageways 52 and 53. The passageways are formed betweeninternal sheets 16 and 17 and external sheets 20 and 21. Panel 13 issealed along lateral side edges 56 and 57.

The detailed construction of each roofing panel is best seen in FIG. 4.Internal fluid passageway 51 is formed between a pair of spacedsubstantially parallel internal sheets 16 and 17 for the passagetherethrough of a fluid, and the external passageways 52 and 53 areformed respectively between internal sheets 16 and 17 and a externalsheets 21 and 20 which are spaced from and substantially parallel torespective internal sheets 16 and 17.

Spacing ribs 18 are located between internal sheets 16 and 17 and formwith the internal sheets a plurality of fluid conduits 19 within fluidpassageway 51. Spacing ribs 22 are located between internal sheet 16 andexternal sheet 21 and form with the sheets a plurality of externalconduits 23 within external passageway 52. Similarly, spacing ribs 24are located between internal sheet 17 and external sheet 20 and formwith the sheets a plurality of external conduits 25 within externalpassageway 53.

Panels 13 can be made from a suitable plastics material such as knowntemperature resistant plastic polycarbonate. The material may betranslucent of tinted on one or both external sheets for aestheticpurposes or for increasing the effectiveness of solar absorption.Alternatively, panels 13 can be made from suitable metal material suchas aluminium or rolled steel which may be powder coated on the outsideof the external sheets to provide desired colouring effects.

As is best seen in FIG. 5 which is a sectional elevation along lines AAin FIG. 2 illustrating the interconnection of adjoining heat exchangerpanels along their sides and their fixing to the roofing frame, panels13 are supported on roofing battens 26. Battens 26 are mountedtransversely of roof rafters 27 (or the top chord of roof trusses) inknown manner. Panels 13 are positioned with their lateral sides aboverafters 27 and joined along their sides by lateral joining strips 28.The panels are fixed to rafters 27 and/or battens 26 by nails 29 throughjoining strips 28.

As is seen in more detail in FIGS. 6 and 7, lateral joining strips 28have a plurality of laterally disposed, outwardly directed andlongitudinally extending ribs 49 separated by inwardly directed groovesor slots 30, and a pair of opposed flanges 42 and 43. A plurality ofapertures 31 extend along the length of strip 28 for receiving nails 29.In use, the lateral edges of sheets 16, 17, 20 and 21 extending beyondthe outermost spacing ribs 18, 22 and 24 are adapted to be closelyreceived in grooves 30 with flanges 42 and 43 being closely receivedabove and below adjoining panels to provide a weatherproof seal alongthe lateral sides of the panels.

Joining strips 28 can be made from suitable plastic, rubberisedmaterial, fibreglass, aluminium or rolled steel. Suitable mastic sealerscan also be used to improve weatherproofing.

Alternatively in an embodiment not illustrated, the joining strips canbe replaced by providing a longitudinally extending female socketarrangement along one side edge adapted to closely receive the otherside of the adjoining sheet in the manner of tongue and grooveattachment.

As is best seen in FIGS. 8 and 9, connection of fluid and gas suppliesto panels 13 is effected by a manifold 32 attached to the panel ends 54and 55. Manifold 32 is a longitudinally extending extrusion having fluidcommunication means in the form of a central channel 38 for the inflowor outflow of fluid to or from fluid conduits 19, and gas communicationmeans in the form of a pair of channels 34 and 35 for the inflow oroutflow of gas to or from external conduits 23 and 25 respectively.Manifold 28 includes receiving means in the form of a central opening 39to central channel 38 for receiving internal sheets 16 and 17, andreceiving means in the form of slots 36 for receiving external sheets 20and 21 whereby the fluid communication means 38 and the gascommunication means 34 and 35 are sealingly connected to the fluidpassageway and the external passageways respectively.

Channels 34 and 35 communicate with the external passageways andexternal conduits 23 and 25 via longitudinally extending slots 40 inlongitudinally extending ribs 37 on either side of central opening 39.Ribs 37 are closely received in external passageways 52 and 53 at theends 54 and 55 of panel 13.

It will be seen that the ends of interior panels 16,17 extend beyond theends of external panels 20,21 thereby facilitating ultrasonic or otherfusion welding of manifold 32 to the interior panels 20,21. Thisprovides a better seal to the internal passageways than is obtained byadhesive bonds and the like.

The fluid or gas supply is connected to manifold 32 by means of a portedcap (not illustrated) which fits closely over one end of the manifoldand has connection flanges for connecting gas and/or water lines to themanifold. A blind cap seals the other end of the manifold.

The manifold can be of a standard length corresponding to the width of aheat exchanger panel. Alternatively the manifold can be of variablelength which is cut to a required length to suit individualinstallations with one manifold extending across a number of adjoiningpanels.

As with joining strips 28, manifolds 32 can be made from suitableplastic, rubberised material, fibreglass, aluminium or rolled steel.Suitable mastic sealers can also be used to improve the seal between themanifold and the ends of the panel.

In use, a method of heat exchange in accordance with the presentinvention is effected by passing fluid through internal fluid passageway51 formed between internal sheets 16 and 17, whereby heat is exchangedbetween the fluid and gas in external passageways 52 and 53 formedbetween internal sheet 16 and 17 and a respective external sheet 21 and20.

As can be seen in FIG. 9, a riser 60 extends from the uppermost manifold32 and vents to atmosphere to provide a pressure relief mechanism in thefluid passageway to relieve excess pressures which may be generatedduring heating of the fluid. Riser 60 comprises a U-tube whichcommunicates with central fluid channel 38 in the manifold. A ball valveor the like (not shown) can be included in the down stream leg of theU-tube.

It will be appreciated that the heat exchange panel of the presentinvention has a number of advantages of known systems.

The external passageways of the present invention provide a layerbetween the fluid passageway and the ambient conditions and depending onthe gas therein improves the efficiency of absorption of solar radiationor, in providing an insulating layer can improve the effectiveness ofretention of heat generated by solar radiation.

The multiple passageway construction allows the cooling and heatingproperties of gases such as free air and inert gases to be exploited.The gas carrying external passageways moreover enable the heat exchangerassembly of the present invention to function in conditions where solarradiation is minimal or non-existent.

The venting of the panels ensures that the operating pressure within thefluid circuit is consistent with atmospheric pressure thereby avoidingpressure induced failure of the panel.

It will of course be realised that whilst the above has been given byway of an illustrative example of this invention, all such and othermodifications and variations hereto, as would be apparent to personsskilled in the art, are deemed to fall within the broad scope and ambitof this invention as is herein set forth.

1. A roofing panel incorporating a heat exchange assembly, said roofingpanel including: an internal fluid passageway formed between a pair ofspaced substantially parallel internal sheets for the passagetherethrough of a fluid; respective external passageways formed betweeneach said internal sheet and a respective external sheet spaced from andsubstantially parallel to a respective internal sheet, spacing ribsbetween said sheets and forming with said sheets a plurality of fluidconduits within said internal fluid passageway and a plurality ofexternal conduits within said external passageways; said pair ofinternal sheets at the ends of said internal passageway extending beyondsaid external sheets at the ends of said external passageways therebyfacilitating fusion welding to said internal sheets at the ends of saidinternal passageway, said panel being sealed at the sides thereof bysaid spacing ribs and being open at the ends thereof to provide accessto said conduits which extend from one end of the panel to the other endthereof, and said internal passageway or said external passageways beingadapted to receive or contain a gas for effecting heat exchange with afluid in the other of said internal passageway or said externalpassageways; and at least one manifold having a fluid communicationmeans for the inflow or outflow of a fluid to or from said fluidconduits, and a gas communication means for the inflow or outflow of agas to or from the external conduits.
 2. A roofing panel as claimed inclaim 1 wherein said manifold includes: a receiving means for receivingthe internal sheets and the external sheets whereby said fluidcommunication means and said gas communication means are sealinglyconnected to the fluid passageway and the external passagewaysrespectively.
 3. A roofing panel as claimed in claim 1, wherein saidmanifold is an extrusion and said fluid communication means and said gascommunication means are channels in said extrusion.